Bordkanone75
Much better now, except for that bottom tail, which (despite some cosmetic alterations) isn't much different.
Here's my take on the tail:
As a general rule (applied with common sense, of course), remember that during re-sizing to needed size, the source drawings tend to get deformed a bit (as their content need to be squeezed into smaller amount of "full" pixels). So during drawing it's actually unwise to literally follow them pixel-by-pixel too closely - after all, contours planes (or land vehicles or ships) are generally made of straight lines or fairly regular arcs/curves, so the point is to replicate these "actual" lines, rather than the pixels of the source.